Process for the preparation of surfactant alcohols and surfactant alcohol ethers, the prepared products and their use

ABSTRACT

The invention describes a process for the preparation of surfactant alcohols and surfactant alcohol ethers which are, inter alia, highly suitable as surfactants or for the preparation of surfactants. The process, starting from olefin mixtures which comprise less than 30% by weight of linear hexene isomers and utilizing a catalyst which contains nickel, prepares olefin mixtures having a predominant fraction of branched dodecenes, which are subsequently derivatized to give surfactant alcohols and then optionally alkoxylated. 
     The invention further relates to the use of the surfactant alcohols and surfactant alcohol ethers for the preparation of surfactants by glycosidation or polyglycosidation, sulfation or phosphation.

The present invention relates to a process for the preparation ofsurfactant alcohols and surfactant alcohol ethers which, inter alia, arehighly suitable as surfactants or for the preparation of surfactants.The process, starting from olefin mixtures, produces mixtures having apredominant fraction of branched decenes, which are subsequentlyderivatized to give surfactant alcohols and then optionally isalkoxylated.

The invention further relates to the use of the surfactant alcohols andsurfactant alcohol ethers for the preparation of surfactants byglycosidation or polyglycosidation, sulfation or phosphation.

Fatty alcohols having chain lengths from C₈ to C₁₈ are used for thepreparation of nonionic surfactants. They are reacted with alkyleneoxides to give the corresponding fatty alcohol ethoxylates. (Chapter 2.3in: Kosswig/Stache, “Die Tenside” [Surfactants], Carl Hanser Verlag,Munich Vienna (1993)). The chain length of the fatty alcohol influencesvarious surfactant properties, such as, for example, wetting ability,foam formation, ability to dissolve grease, cleaning power.

Fatty alcohols having chain lengths from C₈ to C₁₈ can also be used forpreparing anionic surfactants, such as alkyl phosphates and alkyl etherphosphates. Instead of phosphates, it is also possible to prepare thecorresponding sulfates. (Chapter 2.2. in: Kosswig/Stache “Die Tenside”[Surfactants], Carl Hanser Verlag, Munich Vienna (1993)).

Such fatty alcohols are obtainable from native sources, e.g. from fatsand oils, or else in a synthet ic ma nner by construction from buildingblocks having a lower number of carbon atoms. One variant here is thedimerization of an olefin to give a product having twice the number ofcarbon atoms and its functionalization to give an alcohol.

Linear olefins of suitable chain length are currently accessible mainlyby two processes:

In the Fischer-Tropsch synthesis, as well as paraffins, olefin isomermixtures form as coupling products.

The oligomerization of ethylene has established itself as a furthersource for obtaining suitable olefins on an industrial scale. In thisprocess, the catalysts used are alkylaluminums and also homogeneousnickel catalysts, as in the case of the known SHOP process from Shell(Weissermel/Arpe, Industrielle organische Chemie [Industrial OrganicChemistry]).

Olefin fractions of suitable chain length are further processed to givesurfactant alcohols. The use of ethylene has the disadvantage of highfeed material costs for the monomer building block. Processes for thepreparation of surfactants which are based on ethylene as startingmaterial are therefore important economically.

For the dimerization of olefins, a number of processes are known. Forexample, the reaction can be carried out over a heterogeneous cobaltoxide/carbon catalyst (FR-A-1 403 273), in the presence of acids such assulfuric or phosphoric acid (FR 964 922), with an alkylaluminum catalyst(WO 97/16398), or with a homogeneously dissolved nickel complex catalyst(U.S. Pat. No. 4,069,273). According to the details in U.S. Pat. No.4,069,273, the use of these nickel complex catalysts (the complexingagent used being 1,5-cyclooctadiene or1,1,1,5,5,5-hexafluoropentane-2,4-dione) gives highly linear olefinswith a high proportion of dimerization products.

FR-A-1 274 529 describes the Lewis-acid-catalyzed dimerization ofmethylpentenes, where the Lewis acid used is boron trifluoride. Thisprocess has the disadvantage that it is difficult to separate off thecatalyst from the reaction product. As a result, not only are productscontaminated with catalyst residues obtained, but the catalyst loss isalso considerable.

DE-A 43 39 713 relates to a process for the oligomerization ofunbranched C₂- to C₆-olefines and to catalysts being optimized in a waythat they supply in the said process as intended very high portions oflinear reaction products. In examples 3 and 5 butane/butene-mixtures areoligomerized resulting in reaction mixtures comprising 62 to 78 percentby weight of octene.

Functionalization of the olefins to give alcohols with extension of thecarbon skeleton about a carbon atom advantageously takes place via thehydroformylation reaction, which gives a mixture of aldehydes andalcohols, which can then be hydrogenated to give alcohols. Approximately7 million metric tons of products per annum are produced worldwide usingthe hydroformylation of olefins. An overview of catalysts and reactionconditions for the hydroformylation process is given, for example, byBeller et al. in Journal of Molecular Catalysis, A104 (1995), 17-85 andalso in Ullmann's Encyclopedia of Industrial Chemistry, vol. A5 (1986),page 217 et seq., page 333, and the relevant literature references.

GB-A 1,471,481 relates to a process for the hydroformylation of olefinesusing a cobalt containing catalyst. The olefines as applied are linearand supply consequently only a few branched oxo alcohols and aldehydes.

DE-A 196 04 466 relates to aqueous compositions comprising analkylpolyglycoside and a polyethyleneglycol derivative of Formula I asdefined. The alkyl rest contained in the polyglycoside (page 2, line 55)is said to have 8 to 18, preferably 10 to 16 C-atoms; there are nodirect indications about its degree of branching. The wording of page 3,line 11, i.e., the alkyl rest as being produced from fatty alcoholsitself resulting from hydrogenation of native fatty acids, allows theinterpretation that they are mostly linear alkyl rests.

From WO 98/23566 it is known that sulfates, alkoxylates, alkoxysulfatesand carboxylates of a mixture of branched alkanols (oxo alcohols)exhibit good surface activity in cold water and have goodbiodegradability. The alkanols in the mixture used have a chain lengthof greater than 8 carbon atoms, having on average from 0.7 to 3branches. The alkanol mixture can be prepared, for example byhydroformylation, from mixtures of branched olefins which for their partcan be obtained either by skeletal isomerization or by dimerization ofinternal, linear olefins.

A given advantage of the process is that no C₃- or C₄-olefin stream isused for the preparation of the dimerization feed. It follows from thisthat, according to the current prior art, the olefins subjected todimerization therein must have been prepared from ethylene (e.g. SHOPprocess). Since ethylene is a relatively expensive starting material forsurfactant manufacture, ethylene-based processes have a disadvantage interms of cost compared with processes which start from C₃- and/orC₄-olefin streams.

The structure of the components of the oxo alkanol mixture depends onthe type of olefin mixture which has been subjected to hydroformylation.Olefin mixtures which have been obtained by skeletal isomerization fromalpha-olefin mixtures lead to alkanols which are branched predominantlyat the ends of the main chain, i.e. in positions 2 and 3, calculatedfrom the end of the chain in each case.

The surface-active end products are obtained from the alkanol mixtureseither by oxidation of the —CH₂OH group to give the carboxyl group, orby sulfation of the alkanols or their alkoxylates.

Similar processes for the preparation of surfactants are described inthe PCT Patent Application WO 97/38957 and in EP-A-787 704. Also in theprocesses described therein, an alpha-olefin is dimerized to give amixture of predominantly vinylidene-branched olefin dimers:

The vinylidene compounds are then double-bond-isomerized, such that thedouble bond migrates from the end of the chain further into the center,and are then subjected to hydroformylation to give an oxo alcoholmixture. The latter is then further reacted, e.g. by sulfation to givesurfactants. A serious disadvantage of this process is that it startsfrom alpha-olefins. Alpha-olefins are obtained, for example, bytransition-metal-catalyzed oligomerization of ethylene, Ziegler build-upreaction, wax cracking or Fischer-Tropsch processes and are thereforerelatively expensive starting materials for the manufacture ofsurfactants. A further considerable disadvantage of this knownsurfactant preparation process is that a skeletalisomerization must beinserted in the process between the dimerization of the alpha-olefinsand the hydroformylation of the dimerization product if predominantlybranched products are desired. Because it uses a starting material whichis relatively expensive for surfactant manufacture and because of theneed to insert an additional process step, the isomerization, this knownprocess is at a considerable disadvantage in terms of cost.

U.S. Pat. No. 5,780,694 describes the preparation and use of alcoholshaving degrees of branching between 0.9 and 2. The alcohols are preparedby homogeneously catalyzed dimerization of internal olefins andsubsequent hydroformylation, where the n-proportion in the olefin to bedimerized is more than 85% by weight. A particular advantage of thesealcohols is given as the cold washing behavior of their sulfates.Information about the properties of the corresponding ethoxylates andsulfates thereof is not given in this publication. A further advantageof this process is given as being the fact that, for the preparation ofthe alcohols, no propene- or butene-containing olefin mixtures are used,but mixtures which comprise at least 85% by weight of C₆- toC₁₀-olefins.

From the discussed disadvantages of the prior art, in particular alsofrom the need to reduce the preparation costs, arises the object ofproviding a process for the preparation of surfactant alcohols which areadvantageous in terms of application, in which the use of expensive rawmaterials, in particular costly ethylene, can be avoided.

Surprisingly, we have now found that branched olefins and alcohols (oxoalcohols), which can be further processed to give very highly effectivesurfactants—referred to below as “surfactant alcohols”—and which haveparticularly advantageous properties with regard to ecotoxicity andbiodegradability, can be obtained if the process is carried outaccording to the invention as described below.

The present invention thus relates to a process for the preparation ofsurfactant alcohols and corresponding surfactant alcohol ethers by

a) dimerization of olefin mixtures,

b) derivatization to give primary alcohols, and

c) optional subsequent alkoxylation,

which comprises using for the dimerization a catalyst containing nickel,and an olefin mixture comprising essentially C₆- to C₁₂-olefins, whichcomprises at least 55% by weight of hexene isomers, where the hexeneisomer fraction has less than 30% by weight of linear isomers.

Preferably, process step a), the dimerization, is carried out withheterogeneous catalysis. It is also preferable to use an olefin mixturewhich comprises at least 65% by weight of hexene isomers.

Particular preference is given to the use of so-called dimer propene asolefin mixture in step a) of the process according to the invention. Theterm “dimer propene” means a hexene isomer mixture which is formed inrefinery processes during the oligomerization of propene, e.g. by the®DIMERSOL process (cf. Cornils/Herrmann, Applied Homogeneous Catalysis,Verlag Chemie (1996)).

In the dimerization of hexene isomer mixtures (step a) of the processaccording to the invention, dimerization products are obtained which,with regard to further processing to surfactant alcohols, haveparticularly favorable components and a particularly advantageouscomposition when the composition of the nickel catalyst and the reactionconditions are chosen such that a dimer mixture is obtained whichcomprises less than 10% by weight of compounds which have a structuralelement of the formula I (vinylidene group)

in which A¹ and A² are aliphatic hydrocarbon radicals.

The dimerization can be carried out with homogeneous or heterogeneouscatalysis. Preference is given to the heterogeneous procedure since withthis, on the one hand, catalyst removal is simplified, making theprocess more economical, and on the other hand no waste waters injuriousto the environment are produced, as usually form during the removal ofdissolved catalysts, for example by hydrolysis. Another advantage of theheterogeneous process is that the dimerization product does not containhalogens, in particular chlorine or fluorine. Homogeneously solublecatalysts generally contain halide-containing ligands or are used incombination with halogen-containing cocatalysts. From such catalystsystems, halogen can be incorporated into the dimerization products,which considerably adversely affects both product quality and furtherprocessing, in particular hydroformylation to give surfactant alcohols.

For the heterogeneous catalysis, use is advantageously made ofcombinations of nickel oxides with aluminum oxide on support materialsmade from silicon and titanium oxides, as are known, for example, fromDE-A-43 39 713. The heterogeneous catalyst can be used in a fixedbed—then preferably in coarsely particulate form as 1 to 1.5 mm chips—orin suspended form (particle size 0.05 to 0.5 mm). In the case of aheterogeneous procedure, the dimerization is advantageously carried outat temperatures of from 80 to 200° C., preferably from 100 to 180° C.,at the pressure prevailing at the reaction temperature, optionally alsounder a protective gas at a pressure above atmospheric, in a closedsystem. To achieve optimal conversions, the reaction mixture isadvantageously circulated repeatedly, a certain proportion of thecirculating product being continuously bled out of the system andreplaced by starting material.

In the dimerization according to the invention, mixtures ofmonounsaturated hydrocarbons are obtained whose components predominantlyhave a chain length twice that of the starting olefins.

A characteristic feature of the olefin mixtures prepared according tothe invention is their high proportion—usually greater than 90%, inparticular greater than 95%—of components containing branches and thelow proportion—usually less than 10%, in particular less than 5%—ofunbranched olefins. A further characteristic is that predominantlymethyl or ethyl groups are bonded to the branching sites of the mainchain.

The novel olefin mixtures obtainable by step a) of the process accordingto the invention and having the structural features given above arelikewise provided by the present invention. They are usefulintermediates, in particular for the preparation, described in moredetail below and carried out in accordance with step b) of the processaccording to the invention, of branched primary alcohols andsurfactants, but can also be used as starting materials in otherindustrial processes which start from olefins, particularly when the endproducts are to have improved toxicological properties.

If the olefin mixtures according to the invention are to be used for thepreparation of surfactants, then they are firstly derivatized inaccordance with step b) of the process according to the invention bymethods known per se to give surfactant alcohols.

This can be achieved in a variety of ways, which either include thedirect or indirect addition of water (hydration) to the double bond, oran addition of CO and hydrogen (hydroformylation) to the C═C doublebond.

Hydration of the olefins resulting from process step a) isadvantageously carried out by direct water addition with protoncatalysis. An indirect route, for example via the addition ofhigh-percentage sulfuric acid to give an alkanol sulfonate andsubsequent hydrolysis to give the alkanol, is, of course, also possible.The more advantageous direct water addition is carried out in thepresence of acidic, in particular heterogeneous, catalysts and generallyat a very high olefin partial pressure and at very low temperatures.Suitable catalysts have proven to be, in particular, phosphoric acid onsupports such as, for example, SiO₂ or Celite, or else acidic ionexchangers. The choice of conditions depends on the reactivity of theolefins to be reacted and can routinely be ascertained by preliminaryexperiments (lit.: e.g. A. J. Kresge et al. J. Am. Chem. Soc. 93, 4907(1971); Houben-Weyl vol. 5/4 (1960), pages 102-132 and 535-539).Hydration generally leads to mixtures of primary and secondary alkanols,in which the secondary alkanols predominate.

For the preparation of surfactants, it is more favorable to start fromprimary alkanols. It is therefore preferable to effectderivatization—step b) of the process according to the invention—of theolefin mixtures obtained from step a) by reaction of same with carbonmonoxide and hydrogen in the presence of suitable, preferably cobalt- orrhodium-containing, catalysts to give branched primary alcohols.(Hydroformylation).

A good overview of the process of hydroformylation with numerous otherliterature references can be found, for example, in the extensivearticle by Beller et al. in Journal of Molecular Catalysis, A104 (1995)17-85 or in Ullmann's Encyclopedia of Industrial Chemistry, vol. A5(1986), page 217 et seq., page 333, and the relevant literaturereferences.

The comprehensive information given therein allows the person skilled inthe art to hydroformylate even the mixtures of branched olefins obtainedin step a) of the process according to the invention. In this reaction,CO and hydrogen are added to olefinic double bonds, giving mixtures ofaldehydes and alkanols according to the following reaction equation:

The molar ratio of n- and iso-compounds in the reaction mixture isusually in the range from 1:1 to 20:1 depending on the hydroformylationprocess conditions chosen and the catalyst used. The hydroformylation isnormally carried out in the temperature range from 90 to 200° and at aCO/H₂ pressure of from 2.5 to 35 MPa (25 to 350 bar). The mixing ratioof carbon monoxide to hydrogen depends on whether the intention is toproduce alkanals or alkanols in preference. The CO:H₂ ratio isadvantageously from 10:1 to 1:10, preferably from 3:1 to 1:3, where, forthe preparation of alkanals, the range of low hydrogen partial pressuresis chosen, and for the preparation of alkanols the range of highhydrogen partial pressures is chosen, e.g. CO:H₂=1:2.

Suitable catalysts are mainly metal compounds of the formula HM(CO)₄ orM₂(CO)₈, where M is a metal atom, preferably a cobalt, rhodium orruthenium atom.

Generally, under hydroformylation conditions, the catalysts or catalystprecursors used in each case form catalytically active species of theformula H_(x)M_(y)(CO)_(z)L_(q), in which M is a metal of subgroup VIII,L is a ligand, which can be a phosphine, phosphite, amine, pyridine orany other donor compound, including in polymeric form, and q, x, y and zare integers depending on the valency and type of metal, and thecovalence of the ligand L, where q can also be 0.

The metal M is preferably cobalt, ruthenium, rhodium, palladium,platinum, osmium or iridium and in particular cobalt, rhodium orruthenium.

Suitable rhodium compounds or complexes are, for example, rhodium(II)and rhodium(III) salts, such as rhodium(III) chloride, rhodium(III)nitrate, rhodium(III) sulfate, potassium rhodium sulfate, rhodium(II) orrhodium(III) carboxylate, rhodium(II) and rhodium(III) acetate, rhodium(III) oxide, salts of rhodium(III) acid, such as, for example,trisammonium hexachlororhodate(III). Also suitable are rhodium complexessuch as rhodium biscarbonylacetylacetonate,acetylacetonatobisethylenerhodium(I). Preference is given to usingrhodium biscarbonylacetylacetonate or rhodium acetate.

Suitable cobalt compounds are, for example, cobalt(II) chloride,cobalt(II) sulfate, cobalt(II) carbonate, cobalt(II) nitrate, theiramine or hydrate complexes, cobalt carboxylates, such as cobalt acetate,cobalt ethylhexanoate, cobalt naphthenate, and the cobalt caprolactamatecomplex. Here, too, it is possible to use the carbonyl complexes ofcobalt, such as dicobalt octacarbonyl, tetracobalt dodecacarbonyl andhexacobalt hexadecacarbonyl.

Said compounds of cobalt, rhodium and ruthenium are known in principleand are described adequately in the literature, or they can be preparedby the person skilled in the art in a manner analogous to that forcompounds already known.

The hydroformylation can be carried out with the addition of inertsolvents or diluents or without such an addition. Suitable inertadditives are, for example, acetone, methyl ethyl ketone, cyclohexanone,toluene, xylene, chlorobenzene, methylene chloride, hexane, petroleumether, acetonitrile, and the high-boiling fractions from thehydroformylation of the dimerization products.

If the resulting hydroformylation product has too high an aldehydecontent, this can be removed in a simple manner by hydrogenation, forexample using hydrogen in the presence of Raney nickel or using othercatalysts known for hydrogenation reactions, in particular catalystscontaining copper, zinc, cobalt, nickel, molybdenum, zirconium ortitanium. In the process, the aldehyde fractions are largelyhydrogenated to give alkanols. A virtually residue-free removal ofaldehyde fractions from the reaction mixture can, if desired, beachieved by posthydrogenation, for example under particularly mild andeconomical conditions using an alkali metal borohydride.

The mixtures of branched primary alkanols, preparable byhydroformylation of the novel olefin mixtures resulting from step a) ofthe process according to the invention, are likewise provided by thepresent invention.

Nonionic or anionic surfactants can be prepared from the alkanolsaccording to the invention in different ways.

Nonionic surfactants are obtained by reacting the alkanols with alkyleneoxides (alkoxylation) of the formula II

in which R¹ is hydrogen or a straight-chain or branched aliphaticradical of the formula C_(n)H_(2n+1), and n is a number from 1 to 16,preferably from 1 to 8. In particular, R¹ is hydrogen, methyl or ethyl.

The alkanols according to the invention can be reacted with a singlealkylene oxide species or with two or more different species. Thereaction of the alkanols with the alkylene oxides forms compounds whichin turn carry an OH group and can therefore react afresh with onemolecule of alkylene oxide. Therefore, depending on the molar ratio ofalkanol to alkylene oxide, reaction products are obtained which havepolyether chains of varying length. The polyether chains can containfrom 1 to about 200 alkylene oxide structural groups. Preference isgiven to compounds whose polyether chains contain from 1 to 10 alkyleneoxide structural groups.

The chains can consist of identical chain members, or they can havedifferent alkylene oxide structural groups which differ from one anotherby virtue of their radical R¹. These various structural groups can bepresent within the chain in random distribution or in the form ofblocks.

The reaction equation below serves to illustrate the alkoxylation of thealkanols according to the invention using, as example, a reaction withtwo different alkylene oxides which are used in varying molar amounts xand y.

R¹ and R^(1a) are different radicals within the scope of the definitionsgiven for R¹, and R²—OH is a branched alkanol according to theinvention.

The alkoxylation is preferably catalyzed by strong bases, which areadvantageously added in the form of an alkali metal hydroxide oralkaline earth metal hydroxide, usually in an amount of from 0.1 to 1%by weight, based on the amount of the alkanol R²—OH (cf. G. Gee et al.,J. Chem. Soc. (1961), p. 1345; B. Wojtech, Makromol. Chem. 66, (1966),p. 180).

Acidic catalysis of the addition reaction is also possible. As well asBronsted acids, Lewis acids, such as, for example, AlCl₃ or BF₃, arealso suitable (cf. P. H. Plesch, The Chemistry of CationicPolymerization, Pergamon Press, New York (1963)).

The addition reaction is carried out at temperatures of from about 120to about 220° C., preferably from 140 to 160° C., in a sealed vessel.The alkylene oxide or the mixture of different alkylene oxides isintroduced into the mixture of alkanol mixture according to theinvention and alkali under the vapor pressure of the alkylene oxidemixture prevailing at the chosen reaction temperature. If desired, thealkylene oxide can be diluted by up to about 30 to 60% using an inertgas. This leads to additional security against explosive polyaddition ofthe alkylene oxide.

If an alkylene oxide mixture is used, then polyether chains are formedin which the various alkylene oxide building blocks are distributed in avirtually random manner. Variations in the distribution of the buildingblocks along the polyether chain arise due to varying reaction rates ofthe components and can also be achieved arbitrarily by continuousintroduction of an alkylene oxide mixture of a program-controlledcomposition. If the various alkylene oxides are reacted successively,then polyether chains having block-like distribution of the alkyleneoxide building blocks are obtained.

The length of the polyether chains varies within the reaction product ina random manner about a mean, which essentially corresponds to thestoichiometric value arising from the amount added.

The alkoxylates preparable starting from alkanol mixtures and olefinmixtures according to the invention are likewise provided by the presentinvention. They exhibit very good surface activity and can therefore beused as neutral surfactants in many areas of application.

Starting from the alkanol mixtures according to the invention, it isalso possible to prepare surface-active glycosides and polyglycosides(oligoglycosides). These substances too have very good surfactantproperties. They are obtained by single or multiple reaction(glycosidation, polyglycosidation) of the alkanol mixtures according tothe invention with mono-, di- or polysaccharides with the exclusion ofwater and with acid catalysis. Suitable acids are, for example, HCl orH₂SO₄. As a rule, the process produces oligoglycosides having randomchain length distribution, the average degree of oligomerization beingfrom 1 to 3 saccharide radicals.

In another standard synthesis, the saccharide is firstly acetalated withacid catalysis with a low molecular weight alkanol, e.g. butanol, togive butanol glycoside. This reaction can also be carried out withaqueous solutions of the saccharide. The lower alkanol glycoside, forexample butanol glycoside, is then reacted with the alkanol mixturesaccording to the invention to give the desired glycosides according tothe invention. After the acidic catalyst has been neutralized, excesslong-chain and short-chain alkanols can be removed from the equilibriummixture, e.g. by distillation under reduced pressure.

Another standard method proceeds via the O-acetyl compounds ofsaccharides. The latter are converted, using hydrogen halide preferablydissolved in glacial acetic acid, into the correspondingO-acetylhalosaccharides, which react in the presence of acid-bindingagents with the alkanols to give the acetylated glycosides.

Preferred for the glycosidation of the alkanol mixtures according to theinvention are monosaccharides, either hexoses, such as glucose,fructose, galactose, mannose, or pentoses, such as arabinose, xylose orribose. Particular preference for glycosidation of the alkanol mixturesaccording to the invention is glucose. It is, of course, also possibleto use mixtures of said saccharides for the glycosidation. Glycosideshaving randomly distributed sugar radicals are obtained, depending onthe reaction conditions. The glycosidation can also take place severaltimes, resulting in polyglycoside chains being added to the hydroxylgroups of the alkanols. In a polyglycosidation using differentsaccharides, the saccharide building blocks can be randomly distributedwithin the chain or form blocks of the same structural groups.

Depending on the reaction temperature chosen, furanose or pyranosestructures can be obtained. To improve the solubility ratios, thereaction can also be carried out in suitable solvents or diluents.

Standard processes and suitable reaction conditions have been describedin various publications, for example in “Ullmann's Encyclopedia ofIndustrial Chemistry”, 5th edition vol. A25 (1994), pages 792-793 and inthe literature references given therein, by K. Igarashi, Adv. Carbohydr.Chem. Biochem. 34, (1977), pp. 243-283, by Wulff and Rohle, Angew. Chem.86, (1974), pp. 173-187, or in Krauch and Kunz, Reaktionen derorganischen Chemie [Reactions in Organic Chemistry], pp. 405-408,Huthig, Heidelberg, (1976).

The glycosides and polyglycosides (oligoglycosides) preparable startingfrom alkanol mixtures and olefin mixtures according to the invention arelikewise provided by the present invention.

Both the alkanol mixtures according to the invention and the polyethersprepared therefrom can be converted into anionic surfactants byesterifying them in a manner known per se with sulfuric acid or sulfluicacid derivatives to give acidic alkyl sulfates or alkyl ether sulfates(sulfating), or with phosphoric acid or its derivatives to give acidicalkyl phosphates or alkyl ether phosphates (phosphating). Sulfatingreactions of alcohols have already been described, e.g. in U.S. Pat. No.3,462,525, 3,420,875 or 3,524,864. Details on carrying out this reactioncan also be found in “Ullmann's Encyclopedia of Industrial Chemistry”,5th edition vol. A25 (1994), pages 779-783 and in the literaturereferences given therein.

If sulfuric acid itself is used for the esterification, then from 75 to100% strength by weight, preferably from 85 to 98% strength by weight,of acid is advantageously used (so-called “concentrated sulfuric acid”or “monohydrate”). The esterification can be carried out in a solvent ordiluent if one is desired for controlling the reaction, e.g. theevolution of heat. In general, the alcoholic reactant is initiallyintroduced, and the sulfating agent is gradually added with continuousmixing. If complete esterification of the alcohol component is desired,the sulfating agent and the alkanol are used in a molar ratio from 1:1to 1:1.5, preferably from 1:1 to 1:1.2. Lesser amounts of sulfatingagent can be advantageous if mixtures of alkanol alkoxylates accordingto the invention are used and the intention is to prepare combinationsof neutral and anionic surfactants. The esterification is normallycarried out at temperatures from room temperature to 85° C., preferablyin the range from 45 to 75° C.

In some instances, it may be advantageous to carry out theesterification in a low-boiling water-immiscible solvent and diluent atits boiling point, the water forming during the esterification beingdistilled off azeotropically.

Instead of sulfuric acid of the concentration given above, for thesulfation of the alkanol mixtures according to the invention it is alsopossible, for example, to use sulfur trioxide, sulfur trioxidecomplexes, solutions of sulfur trioxide in sulfuric acid (“oleum”),chlorosulfonic acid, suirl chloride and also amidosulfonic acid.

The reaction conditions are then adapted appropriately.

If sulfur trioxide is used as sulfating agent, then the reaction canalso be carried out advantageously in a falling-film reactor incountercurrent, if desired also continuously.

Following esterification, the mixtures are neutralized by adding alkaliand, optionally after removal of excess alkali sulfate and any solventpresent, are worked up.

The acidic alkanol sulfates and alkanol ether sulfates and salts thereofobtained by sulfation of alkanols and alkanol ethers according to theinvention and their mixtures are likewise provided by the presentinvention.

In an analogous manner, alkanols and alkanol ethers according to theinvention and mixtures thereof can also be reacted (phosphated) to giveacidic phosphoric esters using phosphating agents.

Suitable phosphating agents are mainly phosphoric acid, polyphosphoricacid and phosphorus pentoxide, but also POCl₃ when the remaining acidchloride fimctions are subsequently hydrolyzed. The phosphation ofalcohols has been described, for example, in Synthesis 1985, pages 449to 488.

The acidic alkanol phosphates and alkanol ether phosphates obtained byphosphation of alkanols and alkanol ethers according to the inventionand their mixtures are also provided by the present invention.

Finally, the use of the alkanol ether mixtures, alkanol glycosides andthe acidic sulfates and phosphates of the alkanol mixtures and of thealkanol ether mixtures preparable starting from the olefin mixturesaccording to the invention as surfactants is also provided by thepresent invention.

The working examples below illustrate the preparation and use of thesurfactants according to the invention.

EXAMPLE 1 Dimerization of Hexene Isomer Mixtures

An isothermally heatable reactor with a diameter of 16 mm was chargedwith 100 ml of a catalyst having the following composition:

50% by weight of NiO, 34% by weight of SiO₂, 3% by weight of TiO₂, 3% byweight of Al₂O₃ (as in DE-A-43 39 713), conditioned for 24 hours at 160°C. in N₂, used as chips measuring from 1 to 1.5 mm.

Four experiments were carried out on each of two olefin mixturescomprising predominantly hexene isomers and of varying composition, thereaction conditions being varied. The composition of the olefin mixturesused is given in Tables 1 and 2; the hexene isomer fraction in each caseconsisted of 71% by weight of methylpentenes, 22% by weight of n-hexenesand 7% by weight of dimethylbutenes.

The olefin mixtures were passed through the fixed catalyst bed at a rate(WHSV), based on the reactor volume, of 0.25 kg/l*h, and were bled outof the system at a rate of from 24 to 28 g/h. The parameters varied inthe individual experiments were the reaction temperature, the pressureand the operating time of the experiment.

Tables 1 and 2 below show the experimental conditions of the eightexperiments and the results obtained therein.

TABLE 1 Reaction conditions Temperature — 100 120 140 160 [° C.]Pressure [bar] — 20 20 20 25 Experiment time [h] — 12 19 36 60 Feed-Reaction Components stock products Composition [% by weight] C₃ 1.6 — —— — C₆ 73.1 39.9 24.0 28.9 32.1 C₇ to C₁ 18.6 17.8 15.9 17.7 19.1 C₁₂5.1 31.7 44.6 42.6 39.2 >C₁₃ 1.6 10.6 15.5 10.8  9.6 Sulfur [ppm] 5 — —— — Chlorine [ppm] 6 — — — — Conversion* — 45.4 67.2 60.5 56.1 C₁₂selectivity** — 80.2 80.4 84.8 83.2 C₁₂ STY*** — 67   99   94   85  

TABLE 2 Reaction conditions Temperature — 100 120 140 160 [° C.]Pressure [bar] — 20 20 20 25 Experiment time [h] — 12 19 36 60 Feed-Reaction Components stock products Composition [% by weight] C₃ — — — —— C₆ 98.3 64.2 33.5 26.9 31.7 C₇ to C₁₁ 1.1  5.3  3.8  2.8  2.3 C₁₂ 0.627.0 54.4 61.3 58.5 >C₁₃ —  3.5  8.3  9.0  7.5 Sulfur [ppm] <1 — — — —Chlorine [ppm] <1 — — — — Conversion* — 34.7 65.9 72.6 67.8 C₁₂selectivity** — 77.4 83.0 85.0 86.9 C₁₂ STY*** 66   134   152   145   *= based on C₆, ** = initial C₁₂ content taken into account, *** = basedon the desired throughput of 25 g/h

The bled-off product was fractionally distilled. The dodecene mixturehas an iso index of 3.2 (determined by NMR spectroscopy afterhydrogenation).

EXAMPLE 2 Hydroformylation of a Dodecene Mixture According to theInvention

866 g of a dodecene mixture prepared as in Example 1 are hydroformylatedwith 3.26 g of Co₂(CO)₈ at 185° C. and 280 bar of CO/H₂ (vol.ratio=1:1.5) with the addition of 87 g of H₂O in a 2.5 l autoclave withlifter stirrer for 5 hours. Cobalt is removed from the reaction productby oxidation using 10% strength by weight acetic acid with theintroduction of air at 90° C. The oxo product is hydrogenated with theaddition of 10% by weight of water in a 2.5 l stirred reactor in tricklemode over a Co/Mo fixed-bed catalyst at 175° C. and a hydrogen pressureof 280 bar with the addition of 10% by weight of water.

The resulting alcohol mixture is fractionally distilled. For theisolated tridecanol mixture, using ¹H-NMR spectroscopy, a mean of 4.4methyl groups/molecule is determined, corresponding to a degree ofbranching of 3.4.

EXAMPLE 3 Preparation of a Fatty Alcohol Ethoxylate Containing 7 mol/molof Ethylene Oxide

400 g of the alkanol mixture prepared as in Example 2 are introducedwith 1.5 g of NaOH into a dry 2 l autoclave. The autoclave contents areheated to 150° C., and 616 g of ethylene oxide are forced into theautoclave under pressure. After all of the ethylene oxide has beenintroduced into the autoclave, the autoclave is maintained at 150° C.for 30 minutes. Following cooling, the catalyst is neutralized by addingsulfuric acid.

The resulting ethoxylate is a neutral surfactant. It has a cloud pointof 71° C., measured in accordance with DIN 53917, 1% strength by weightin 10% strength by weight aqueous butyldiglycol solution. The surfacetension of a solution of 1 g/l of the substance in water is 26.1 mN/m,measured in accordance with DIN 53914. It exhibits an algal toxicitywhich is very low for this carbon chain length. The EC₅₀ values are, fora degree of ethoxylation of 7,22 mg/l/72 h.

EXAMPLE 4 Preparation of a Fatty Alcohol Ethoxylate Containing 3 mol/molof Ethylene Oxide

600 g of the tridecanol mixture prepared as in Example 2 are introducedwith 1.5 g of NaOH into a dry 2 l autoclave. The autoclave contents areheated to 150° C., and 396 g of ethylene oxide are forced into theautoclave under pressure. After all of the ethylene oxide has beenintroduced into the autoclave, the autoclave is maintained at 150° C.for 30 minutes. Following cooling, the catalyst is neutralized by addingsulfuric acid.

The resulting ethoxylate is a neutral surfactant. It has a cloud pointof 40.3° C., measured in accordance with DIN 53917, 1% strength byweight in 10% strength by weight aqueous butyldiglycol solution. Thesurface tension of a solution of 1 g/l of the substance in water is 25.7mN/m, measured in accordance with DIN 53914.

EXAMPLE 5 Preparation of an Alkyl Phosphate

300 g of the tridecanol mixture prepared as in Example 2 are heated to60° C. in a stirred vessel under nitrogen, and 125 g of polyphosphoricacid are added slowly thereto. During the addition, the temperature mustnot exceed 65° C. Toward the end of the addition, the mixture is heatedto 70° C. and stirred at this temperature for a further hour.

The resulting product is an anionic surfactant. An aqueous solution ofthe substance in water has, at a concentration of 1 g/l, a surfacetension of 28.9 mN/m, measured in accordance with DIN 53914.

EXAMPLE 6 Preparation of an Alkyl Ether Phosphate

560 g of the fatty alcohol ethoxylate mixture prepared as in Example 4are heated to 60° C. in a stirred vessel under nitrogen, and 92 g ofpolyphosphoric acid are added slowly thereto. During the addition, thetemperature must not exceed 65° C. Toward the end of the addition, themixture is heated to 70° C. and stirred at this temperature for afurther hour.

The resulting product is an anionic suffactant. An aqueous solution ofthe substance in water has, at a concentration of 1 g/l, a surfacetension of 36.1 mN/m, measured in accordance with DIN 53914.

EXAMPLE 7 Preparation of an Alkyl Sulfate

190 g of the tridecanol mixture prepared as in Example 2 are heated to60° C. in a stirred vessel under nitrogen, and 98 g of concentratedsulfuric acid are added slowly thereto. During the addition,thetemperature must not exceed 65° C. Toward the end of the addition,the mixture is heated to 70° C. and stirred at this temperature for afurther hour.

The resulting product is an anionic surfactant. An aqueous solution ofthe substance in water has, at a concentration of 1 g/l, a surfacetension of 29.8 mN/m, measured in accordance with DIN 53914.

EXAMPLE 8 Preparation of an Alkyl Ether Sulfate

480 g of the fatty alcohol ethoxylate mixture prepared as in Example 4are heated to 60° C. in a stirred vessel under nitrogen, and 146 g ofconcentrated sulfuric acid are added slowly thereto. During theaddition, the temperature must not exceed 65° C. Toward the end of theaddition, the mixture is heated to 70° C. and stirred at thistemperature for a further hour.

The resulting product is an anionic surfactant. An aqueous solution ofthe substance in water has, at a concentration of 1 g/l, a surfacetension of 35.2 mN/m, measured in accordance with DIN 53914.

We claim:
 1. A process for the preparation of surfactant alcohols and corresponding surfactant alcohol ethers comprising: a) dimerization of an olefin mixture, b) derivatization to give primary alcohols, and c) optional subsequent alkoxylation, wherein the dimerization catalyst comprises nickel, and said olefin mixture comprises C₆ to C₁₂ olefins, which comprises at least 55% by weight of hexene isomers, and wherein the hexene isomer fraction has less than 30% by weight of linear isomers.
 2. A process as claimed in claim 1, wherein the dirnerization process step a) is carried out with heterogeneous catalysis.
 3. A process as claimed in claim 1, wherein said olefm mixture comprises,at least 65% by weight of hexene isomers.
 4. A process as claimed in claim 1, wherein a heterogeneous catalyst is used in process step a) and comprises a combination of nickel oxide and alium oxide, whereby a dimer mixture is obtained which comprises less than 10% by weight of compounds which have a structural element of formula I (vinylidene group)

in which A¹ and A² are aliphatic hydrocarbon radicals.
 5. An olefin mixture prepared by process step a) of the process of claim 1, wherein at least 90% by weight of the components of the dimerization mixture are branched and the branched components of the dimerization mixture carry predominantly methyl or ethyl groups at the branching sites of the main chain.
 6. An olefin mixture as claimed in claim 5, wherein less than 10% by weight of components have a structural element of formula I (vinylidene group)

in which A¹ and A² are aliphatic hydrocarbon radicals.
 7. Surfactant alcohols or alkoxylation products thereof, prepared by a process comprsing a) dimerization of an olefin mixture, b) derivatization to give primary alcohols, and c) optional subsequent alkoxylation, wherein in process step b) and in optional process step c) an olefin mixture of claim 5 is used.
 8. Nonionic surfactants comprising the surfactant alcohol alkoxylation products of claim
 7. 9. A method for the preparation of surfactants comprising: subjecting the surfactant alcohols or alkoxylation products thereof of claim 7, to glycosidation, polyglycosidation, sulfation, or phosphation to produce surfactants.
 10. A method for the preparation of alkanol glycoside and polyglycoside mixtures or of surface-active sulfates or surface-active phosphates by single or multiple reaction (glycosidation, polyglycosidation) of the surfactant alcohols or alkoxylation products thereof of claim 7, with mono-, di- or polysaccharides with the exclusion of water and with acid catalysis or with O-acetylsaccharide halides or by esterification of the surfactant alcohols or alkoxylation products thereof of claim 7 with sulfuric acid or sulfuric acid derivatives to give acidic alkyl sulfates or alkyl ether sulfates or by esterification of the surfactant alcohols or alkoxylation products thereof of claim 7 with phosphoric acid or its derivatives to give acidic alkyl phosphates or alkyl ether phosphates.
 11. An olefmn mixture comprising dimerized C₆ to C₁₂ olefins, which comprises at least 55% of hexene isomers, and wherein the hexene fraction has less than 30% by weight of linear isomers, and wherein at least 90% by weight of the components of the dimerization mixture are branched and the branched components of the dimerization mixture carry predominantly methyl or ethyl groups at the branching sites of the main chain. 